Abstract：
This paper describes the availability of a 1,2-dichloroethane (DCE)-water (W) interfacial system under a controlled interfacial potential difference for the separation of polycationic species. The system was applied to the production of polyethylene glycol-modified ε-poly-L-lysine (PEG-εPL). PEG-εPL is produced by a fermentation process, and the crude product contains a significant amount of non-modified εPL, which is hardly separated by conventional chromatographic techniques. Both εPL species exist in fully protonated forms under certain acidic conditions, and an extractant, dibenzo-18-crown-6 (DB18C6), associates with their ammonium groups to stabilize the polycations in DCE. Despite the polydispersity of the samples, the εPL and crude PEG-εPL give well-defined cyclic voltammetric waves due to the DB18C6-assisted transfer of the polycations at the polarizable DB18C6 (DCE) | (W, pH ~ 3) interface with midpoint potentials useful for a rough prediction of ion partition equilibria. Thus, the partition experiment was performed using the DB18C6, Bu4N[(CF3SO2)2N] (DCE) | crude PEG-εPL, Li[(CF3SO2)2N] (W, pH ~ 3) interfacial system, of which the potential difference was controlled to enable selective extraction of polycationic PEG-εPL by partition of the [(CF3SO2)2N]- ion. The extract could be collected from the DCE phase and was found to consist of highly purified PEG-εPL.
摘要：
本文介绍了在受控的界面电位差下，1,2-二氯乙烷（DCE）-水（W）界面系统的可用性，用于分离聚阳离子物种。将该系统应用于聚乙二醇修饰的ε-聚-L-赖氨酸(PEG-εPL)的生产。PEG-εPL是通过发酵过程生产的，粗产品含有大量的未改性εPL，用常规色谱技术很难分离。在某些酸性条件下，两种εPL都以完全质子化的形式存在，和萃取剂,二苯并-18-冠-6(DB18C6)，与它们的铵基缔合以稳定DCE中的聚阳离子。尽管样品的多分散性，由于可极化DB18C6（DCE）上的聚阳离子的DB18C6辅助转移，εPL和粗PEG-εPL给出了明确定义的循环伏安波|（W，pH〜3）与中点电位的界面，可用于粗略预测离子分配平衡。因此，使用DB18C6，Bu4N[（CF3SO2）2N]（DCE）|粗PEG-εPL进行分配实验，Li[(CF3SO2)2N](W,pH~3)界面体系,控制电位差，以通过分配[（CF3SO2）2N]-离子来选择性萃取聚阳离子PEG-εPL。可以从DCE相收集提取物,发现其由高度纯化的PEG-εPL组成。
